The peculiar character of John's first epistle

The epistle of John has a peculiar character. It is eternal
life manifested in Jesus, and imparted to us -- the life which
was with the Father, and which is in the Son. It is in this life
that believers enjoy the communion of the Father, that they are
in relationship with the Father by the Spirit of adoption, and
that they have fellowship with the Father and the Son. God's own
character is that which tests it; because it proceeds from
Himself.

The first chapter establishes these two latter points:
namely, communion with the Father and the Son, and that this
communion must be according to the essential character of
God. The name of Father is that which gives character to the
second chapter. Afterwards it is that which God is, which tests
the reality of imparted life.

What characterises Paul's epistles and this of John

The epistles of Paul, although speaking of this life, are in
general occupied with setting before Christians the truth
respecting the means of standing in the presence of God justified
and accepted. The epistle of John, that is to say, his first,
shows us the life that comes from God by Jesus Christ. John sets
God before us, the Father revealed in the Son, and eternal life
in Him. Paul sets us before God accepted in Christ. I speak of
what characterises them. Each respectively touches on the other
point.

Eternal life manifested in the Person of Jesus that of the Christian

Now, this life is so precious, manifested as it is in the Person
of Jesus, that the epistle now before us has in this respect
quite a peculiar charm. When I, too, turn my eyes to Jesus, when
I contemplate all His obedience, His purity, His grace, His
tenderness, His patience, His devotedness, His holiness, His
love, His entire freedom from all self-seeking, I can say, That
is my life.

This is immeasurable grace. It may be that it is obscured in me;
but it is none the less true, that that is my life. Oh how do I
enjoy it thus seen! How I bless God for it! What rest to the
soul! What pure joy to the heart! At the same time Jesus Himself
is the object of my affections; and all my affections are formed
on that holy object.*

{*And this is morally very important; while it is in Him, not
in myself, that I rejoice and delight.}